1. Technological Field
The present invention relates to an electronic thermometer, and to a body temperature measurement method.
2. Background Technology
In measuring human body temperature, it is necessary to keep the thermometer under the tongue, under the armpit, in the rectum, or the like until the thermometer reaches temperature equilibrium with the body temperature. These locations reflect the temperature inside the body, referred to as the core temperature, and are generally used for body temperature measurement. A method is also used wherein a heater is mounted in a continuous core thermometer worn continuously on the body surface, and the temperature achieved when the heat current from inside the body, i.e. from the core, and the heat current from the heater become equal to each other is assumed to be the core body temperature. However, the large amount of electrical power and the control that is necessary because of the mounting of the heater result in a bulky device that cannot be used continuously on an everyday basis. Accordingly, unheated core body thermometers have been devised (Patent Documents 1, 2, 3).
In Patent Document 1, the core body temperature is calculated using temperature measuring parts of two systems having two different types of thermal resistance, and consideration is given to the thermal resistance between the temperature measuring parts of the two systems during calculation. In the temperature measuring parts, a thermistor or other temperature sensor is attached to the side close to the skin and to the side exposed to the open air, with a material having a certain thermal resistance being interposed therebetween.
In Patent Documents 2 and 3, temperature measuring parts of two systems using the same thermal resistance are used, the temperature distribution of the two different systems is determined by varying the thermal resistance on the portion in which heat is radiated out into the open air, and the core body temperature is calculated. The thermal resistance between the temperature measuring part and the human body can thereby be eliminated in terms of calculation, and there is no need to know the thermal resistance beforehand. Specifically, it is possible to measure core body temperatures very precisely without any need for the thermal resistance of each person to be measured beforehand.